Internal tensioning structure useable with inflatable devices

ABSTRACT

An internal tensioning structure for use in an inflatable product fulfills the basic function of maintaining two adjacent inflatable surfaces in a desired geometric arrangement when the inflatable product is pressurized. The tensioning structure is formed by connecting a pair of plastic strips sheets via spaced-apart strands, such as strings or wires. When pulled taut, the strands provide a high tensile strength between the two opposed plastic strips. At the same time, the plastic strips facilitate a strong, long-lasting weld between the tensioning structure and the inflatable product.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/935,964, filed Jul. 22, 2020, which is a continuation of U.S. patentapplication Ser. No. 15/581,638, filed Apr. 28, 2017, which is acontinuation of U.S. patent application Ser. No. 14/444,453, filed Jul.28, 2014, now U.S. Pat. No. 9,802,359, which is a continuation of PCTApplication Serial No. PCT/US2012/042079, filed Jun. 12, 2012, whichclaims priority to the four Chinese patent applications listed in thetable below.

The entire disclosures of the above-identified U.S. and PCTApplications, and the below-identified Chinese patent applications, areall expressly incorporated by reference herein.

Chinese Application No. Filing Date 201210053143.X Mar. 2, 2012201210053146.3 Mar. 2, 2012 201220075738.0 Mar. 2, 2012 201220075742.7Mar. 2, 2012

BACKGROUND

The present disclosure relates to an inflatable product structure, andin particular to an inflatable product structure which is light inweight and low in cost.

Inflatable products, are light in weight, easy to house, and easy tocarry. Such products technologies have been used for outdoor items andtoys, as well as various household goods including inflatable beds,inflatable sofas and the like.

Many inflatable products utilize internal structures in order to formthe product into its intended, predetermined shape upon inflation. Forexample, one type of inflatable bed, referred to as a wave-shaped,straight-strip or I-shaped inflatable bed, may include a tension-bandtype internal structure arranged along wave-shaped, straight-line orI-shaped pathways within the internal cavity. Another type of inflatablebed, referred to as a column-type inflatable bed, has tension bandsarranged into honeycomb-shaped or cylindrical structures within theinflatable cavity.

These internal tension-band structures disposed in the cavity of theinflatable bed give shape to the bed as internal pressure increases,thereby preventing the inflatable bed from expanding evenly on all sidesin the manner of a balloon. More particularly, in order to maintain aninflatable bed as a rectangular shape, the tension bands join the upperand lower surfaces of the inflatable bed to one another. To allowpassage of pressurized air to both sides of these joining structures,the tension bands may be formed as belts stretching between the upperand lower surfaces, or as vertical expanses of material with air columnsformed therein. The number and spacing of the tension bands isproportional to the sharpness of the rectangularity of the inflatedproduct. That is to say, a greater number and/or linear extent oftension bands within the pressurized cavity results in a more “flat” bedsurface.

In conventional inflatable products such as the inflatable bedsdescribed above, the tension bands are made of PVC sheets with asufficient thickness to ensure spreading of force and concomitantreductions in stress in the product material. For example, the tensionbands of known inflatable beds or sofas may have a thickness of about0.36 mm. For some known water carrier devices, such as inflatableswimming pools, the internal tension bands may have a thickness of about0.38 mm, while “sandwich” type inflatable swimming pools may have athickness of 0.7-0.8 mm.

Thus, conventional inflatable structures utilizing belt- or sheet-likePVC tension bands meet the force requirements of the product by varyingthe thickness of the tension bands. However, where continuous plasticstrips or belts are utilized, such tension bands contribute to increasedweight of the inflatable product. Similarly, an increase in thicknessand/or spatial density of solid-strip tension bands also increases thecompressed/folded volume of the deflated inflatable structure.

SUMMARY

The present disclosure provides an internal tensioning structure for usein an inflatable product, and a method for producing the same. Thetensioning structure fulfills the basic function of maintaining twoadjacent inflatable surfaces in a desired geometric arrangement when theinflatable product is pressurized. The tensioning structure is formed byconnecting a pair of plastic strips sheets via spaced-apart strands,such as strings or wires. When pulled taut, the strands provide a hightensile strength between the two opposed plastic strips. At the sametime, the plastic strips facilitate a strong, long-lasting weld betweenthe tensioning structure and the inflatable product.

Various configurations of the tensioning structure are contemplatedwithin the scope of the present disclosure. In one embodiment, a pair ofparallel plastic strips has a plurality of strands extendingtherebetween to connect the plastic strips to one another, with thestrands substantially parallel to one another and substantiallyperpendicular to the plastic strips. In another embodiment, a similararrangement of two parallel plastic strips are connected by a pluralityof strands with each adjacent pair of such strands converging to a pointat one of the plastic strips in a “V” configuration. Either embodimentmay be incorporated into a tensioning structure with one of a number ofgeometric arrangements within the inflatable cavity, such as linear,cylindrical, wave-shaped, etc.

According to one embodiment thereof, the present disclosure provides aninflatable product comprising: a first sheet and a second sheet disposedopposite the first sheet, the first and second sheets spaced apart todefine a gap when the inflatable product is inflated. The inflatableproduct further includes a tensioning structure having a gap portionspanning the gap between the first sheet and the second sheet tomaintain a spatial relationship between the first and second sheets whenthe inflatable product is inflated. The gap portion has an extentmeasured along the surface of at least one of the first sheet and thesecond sheet. The gap portion occupies a volume and has an operable areaoccupied by gap portion of the tensioning structure defined as the totalarea of the gap between the first sheet and the second sheet, asmeasured along the extent of the gap portion of the tensioningstructure. The gap portion of the tensioning structure defines anoperable area-to-volume ratio of at least 10 square millimeters percubic millimeter.

According to another embodiment thereof, the present disclosure providesan inflatable product comprising: a first sheet and a second sheetdisposed opposite the first sheet. The first and second sheets arespaced apart to define a gap when the inflatable product is inflated.The inflatable product further includes a tensioning structure having agap portion spanning the gap between the first sheet and the secondsheet to maintain a spatial relationship between the first and secondsheets when the inflatable product is inflated. The gap portion has anextent measured along the surface of at least one of the first sheet andthe second sheet. The gap portion has an operable area occupied by gapportion of the tensioning structure defined as the total area of the gapbetween the first sheet and the second sheet, as measured along theextent of the gap portion of the tensioning structure. The gap portionof the tensioning structure has a total weight such that the tensioningstructure defines an operable area-to-weight ratio of at least 6,000square centimeters per kilogram.

According to another embodiment thereof, the present disclosure providesan inflatable product comprising: a first sheet and a second sheetdisposed opposite the first sheet. The first and second sheets arespaced apart to define a gap when the inflatable product is inflated;The inflatable product further comprises a tensioning structure having agap portion spanning the gap between the first sheet and the secondsheet to maintain a spatial relationship between the first and secondsheets when the inflatable product is inflated. The gap portion of thetensioning structure has an average thickness of less than 0.125millimeters.

According to yet another embodiment thereof, the present disclosureprovides an inflatable product comprising: a first sheet; a second sheetdisposed opposite the first sheet, the first and second sheets spacedapart to define a gap; a tensioning structure spanning the gap betweenthe first sheet and the second sheet, the tensioning structurecomprising: a plurality of strands uniformly spaced apart and arrangedsubstantially parallel to one another; and a plurality of weld stripsspaced apart from one another and substantially perpendicular to theplurality of strands, each of the plurality of weld strips affixed toeach of the plurality of strands, and each of the plurality of weldstrips affixed to at least one of the first sheet and the second sheet.

According to still another embodiment thereof, the present disclosureprovides an inflatable product comprising: a first sheet; a second sheetdisposed opposite the first sheet, the first and second sheets spacedapart to define a gap; a tensioning structure spanning the gap betweenthe first sheet and the second sheet, the tensioning structurecomprising: a plurality of strands uniformly spaced apart and arrangedin parallel; and a first weld sheet having the plurality of strandsaffixed to an upper surface of the first weld sheet.

According to still another embodiment thereof, the present disclosureprovides an inflatable product comprising: a first sheet; a second sheetdisposed opposite the first sheet, the first and second sheets spacedapart to define a gap; a tensioning structure spanning the gap betweenthe first sheet and the second sheet, the tensioning structurecomprising: an upper weld strip; a lower weld strip arrangedsubstantially parallel to the upper weld strip and spaced apart from theupper weld strip span the gap between the first sheet and the secondsheet; and a plurality of end-to-end V-shaped strands arranged betweenweld strips, each of the V-shaped strands having upper and lower endsfixed to the upper and lower weld strips, respectively.

According to still another embodiment thereof, the present disclosureprovides an inflatable product comprising: a first sheet; a second sheetdisposed opposite the first sheet, the first and second sheets spacedapart to define a gap, the first sheet and the second sheet cooperatingto at least partially bound an inflatable chamber; a plurality oftensioning structures welded to respective inner surfaces of the firstand second sheets such that the plurality of tensioning structure spanthe gap, each of the plurality of tensioning structures comprising: anupper weld strip affixed to one of the first sheet and the second sheet;a lower weld strip affixed to the other of the first sheet and thesecond sheet; and a plurality of strands connecting the upper and lowerweld strips to one another.

According to still another embodiment thereof, the present inventionprovides an inflatable product comprising: a first sheet; a second sheetdisposed opposite the first sheet, the first and second sheets spacedapart to define a gap, the first sheet and the second sheet cooperatingto at least partially bound an inflatable chamber; a plurality oftensioning structures welded to inner surfaces of the first and secondsheets such that the plurality of tensioning structures span the gap,each of the plurality of tensioning structures comprising: a weld sheet;a plurality of strands, and the plurality of strands substantiallyevenly spaced and arranged substantially parallel to one another, theplurality of strands affixed to the weld sheet; and a weld strip affixedto each end of the weld sheet such that a longitudinal extent of theweld strip is substantially perpendicular to the plurality of strands,respective ends of the plurality of strands are affixed to the weldstrip, and each of the weld strips are welded to one of the first sheetand the second sheet.

According to still another embodiment thereof, the present inventionprovides a method for producing a tensioning structure of an inflatableproduct, the method comprising: arranging at least one of a welder andan adhesive device downstream of a strand guide; supplying a pluralityof strands to the welder or the adhesive device via the strand guide,such that the supplied strands are substantially uniformly spaced apartand arranged substantially parallel to one another; positioning weldstrips on a first die of the welder or gluing device, the weld stripshaving a longitudinal extent corresponding to an overall width of theplurality of strands; advancing a second die of the welder or gluingdevice into an operable position in which the first and second dies aredisposed at opposing sides of the weld strips, activating the welder orgluing device to fixedly connect the weld strips to the plurality ofstrands, such that the weld strips are affixed to the plurality ofstrands in a spaced apart and substantially parallel arrangement, andsuch that the weld strips are substantially perpendicular to theplurality of strands.

According to still another embodiment thereof, the present inventionprovides a method for producing a tensioning structure of an inflatableproduct comprises: arranging a hot roller downstream of a strand guide;supplying a plurality of strands to the hot roller via the strand guide,such that the supplied strands are substantially uniformly spaced apartand arranged substantially parallel to one another; arranging aconveying roller downstream of the strand guide, the conveying rolleroperable to deliver at least one weld sheet to the hot roller, the atleast one weld sheet having a width corresponding to an overall width ofthe plurality of strands; and passing the plurality of strands and theat least one weld sheet through the hot roller, such that the pluralityof strands become affixed to the at least one weld sheet.

According to still another embodiment thereof, the present inventionprovides a method for producing a tensioning structure, the methodcomprising: arranging a first pair of weld strips parallel to oneanother on a joining device; wrapping at least one continuous strandaround a plurality of members arranged along a pair of rows adjacent thefirst pair of weld strips, respectively, each of the pair of rows ofmembers offset with respect to the other of the pair of rows of members,the step of wrapping comprising alternating between the pair of rows,such that the at least one continuous strand forms a plurality ofend-to-end V-shaped strands; and using the joining device to join thefirst pair of weld strips to the plurality of strands at respectiveV-shaped corners formed by the at least one continuous strand, such thatthe tensioning structure has a tensile strength along a directionperpendicular to a longitudinal extent of the first pair of weld strips.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other features and advantages of thisdisclosure, and the manner of attaining them, will become more apparentand the invention itself will be better understood by reference to thefollowing description of embodiments of the invention taken inconjunction with the accompanying drawings, wherein:

FIG. 1 is an exploded, perspective view of an inflatable structureincorporating a tensioning structure made in accordance with the presentdisclosure;

FIG. 2 is an enlarged perspective view of the tensioning structure shownin FIG. 1 ;

FIG. 3 is an exploded, perspective view of an inflatable bedincorporating tensioning structures made in accordance with the presentdisclosure;

FIG. 4 is an assembled view of the inflatable bed of FIG. 3 , in whichthe inflatable bed material is made transparent to show the internalarrangement of the tensioning structures;

FIG. 5 is an exploded, perspective view of an inflatable bedincorporating an alternative geometric arrangement of tensioningstructures made in accordance with the present disclosure;

FIG. 6 is an assembled view of the inflatable bed of FIG. 5 , in whichthe inflatable bed material is made transparent to show the internalspatial arrangement of the tensioning structures;

FIG. 7 is a perspective view of an apparatus for producing bulk materialfor the tensioning structures shown in FIGS. 3-6 ;

FIG. 8 is an exploded, perspective view showing a first embodiment ofthe bulk material created by the apparatus of FIG. 7 ;

FIG. 9 is a perspective view showing a first embodiment of the bulkmaterial created by the apparatus of FIG. 7 ;

FIG. 10 is a perspective view showing a second embodiment of the bulkmaterial created by the apparatus of FIG. 7 ;

FIG. 11 is a perspective view showing a second embodiment of the bulkmaterial created by the apparatus of FIG. 7 ;

FIG. 12 is an exploded, perspective view of a first alternativetensioning structure made in accordance with the present disclosure;

FIG. 13 is an assembled, perspective view of the first alternativetensioning structure shown in FIG. 12 ;

FIG. 14 is an exploded, perspective view of a second alternativetensioning structure made in accordance with the present disclosure;

FIG. 15 is an exploded, perspective view of a third alternativetensioning structure made in accordance with the present disclosure;

FIG. 16 is an assembled, perspective view of the third alternativetensioning structure shown in FIG. 15 ;

FIG. 17 is an exploded, perspective view of a fourth alternativetensioning structure made in accordance with the present disclosure;

FIG. 18 is an exploded, perspective view of a fifth alternativetensioning structure made in accordance with the present disclosure;

FIG. 19 is an assembled, perspective view of the fifth alternativetensioning structure shown in FIG. 18 ;

FIG. 20 is an exploded, perspective view of an inflatable bedincorporating alternative tensioning structures made in accordance withthe present disclosure;

FIG. 21 is an assembled view of the inflatable bed of FIG. 22 , in whichthe inflatable bed material is made transparent to show the internalarrangement of the tensioning structures;

FIG. 22 is an exploded, perspective view of an inflatable bedincorporating an alternative tensioning structures made in accordancewith the present disclosure, configured in an alternative geometricarrangement;

FIG. 23 is an assembled view of the inflatable bed of FIG. 22 , in whichthe inflatable bed material is made transparent to show the internalspatial arrangement of the tensioning structures;

FIG. 24 is a perspective view of an apparatus for producing bulkmaterial for the first through fifth alternative tensioning structuresshown in FIGS. 12-19 ;

FIG. 25 is an exploded, perspective view of a sixth alternativetensioning structure made in accordance with the present disclosure;

FIG. 26 is an assembled, perspective view of the sixth alternativetensioning structure shown in FIG. 25 ;

FIG. 27 is an exploded, perspective view of an inflatable bedincorporating the sixth alternative tensioning structure shown in FIG.25 ;

FIG. 28 is an assembled view of the inflatable bed of FIG. 27 , in whichthe inflatable bed material is made transparent to show the internalarrangement of the tensioning structures;

FIG. 29 is a perspective view of an apparatus for producing bulkmaterial for the sixth alternative tensioning structures shown in FIGS.25-28 ;

FIG. 30 is an exploded, perspective view of a seventh alternativetensioning structure made in accordance with the present disclosure;

FIG. 31 is an assembled, perspective view of the seventh alternativetensioning structure shown in FIG. 30 ;

FIG. 32 is a perspective view of an apparatus for producing bulkmaterial for the seventh alternative tensioning structures shown inFIGS. 30 and 31 ;

FIG. 33 is a top plan view of portions of tensioning structures bunchedtogether during a welding process;

FIG. 34 is a top plan view of portions of a tensioning structurecollapsed when the mattress is deflated for storage or shipment;

FIG. 35 is a view similar to FIG. 33 showing portions of tensioningstructures with strands placed in piles during a welding process; and

FIG. 36 is a view similar to FIG. 33 showing portions of tensioningstructures shifted relative to each other during a welding process.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate exemplary embodiments of the present invention, and suchexemplifications are not to be construed as limiting the scope of theinvention in any manner.

DETAILED DESCRIPTION

The present disclosure provides tensioning structures which give shapeto inflatable devices, such as inflatable couches, beds or swimmingpools. The tensioning structures are lightweight and occupy minimalvolume when the device is deflated and packed away, while alsofunctioning as a strong and durable internal support upon inflation anduse of the inflatable device.

An exemplary tensioning structure in accordance with the presentdisclosure utilizes thin and flexible string- or wire-like strands whichjoin two areas of fabric to one another. The strands are firmlyconnected to the adjacent fabric via an intermediate material, such as astrip or sheet, and the intermediate material is in turn firmlyconnected to the fabric. The area of contact between intermediatematerial and the attached strands may be manipulated to impart aconnection strength commensurate with the tensile strength of thestrand. Similarly, the area of contact between the intermediate materialand the adjacent fabric may also be manipulated to impart afabric/tensioning structure connection strength commensurate with theaggregate tensile strength of all strands in the tensioning structure.

Various tensioning structures and methods of manufacturing the same aredescribed in detail below. It is contemplated that any of the presentdescribed tensioning structures may be used in any inflatable product,either alone, as a group or in combination with one another as requiredor desired for a particular design. In addition, it is contemplated thattensioning structures in accordance with the present disclosure can beused in other contexts, such as in camping equipment, or in any othercontext where a lightweight, packable structure is needed to join twopieces of material that are urged away from one another in use.

1. Weld Strips Joined By Spaced-Apart Strands.

Turning now to FIGS. 1 and 2 , tensioning structure 3 is shown joiningupper material 1 to lower material 2. In the illustrated embodiment,tensioning structure 3 includes upper and lower weld strips 31 connectedto one another by a plurality of substantially parallel strands 32 thatdefine a gap portion extending between a gap between upper and lowersheets 1, 2. The upper and lower weld strips 31 are in turn welded tothe upper material 1 and the lower material 2, respectively, such thatforces urging upper and lower materials 1, 2 are encountered by tensionin strands 32.

Optionally, reinforcing strands 5 (FIG. 3 ) may be provided along thelongitudinal extent of weld strip 31 (i.e., substantially perpendicularto strands 32). Reinforcing strands 5, when provided, may be coupled totensile strands 32, such as by folding strands 32 over reinforcingstrands 5, tying strands 5, 32 to one another, or adhesively securingstrands 5, 32 to one another. When so coupled, reinforcing strands 5provide additional surface area contact with weld strips 31 and therebyimprove the resistance of securing strands 5 to pulling free from weldstrips 31. In addition, the presence of reinforcing strands 32 withinweld strips 31 improves the tensile strength of weld strips 31 alongtheir longitudinal extents.

The plurality of strands 32 in the tensioning structure 3 as shown inFIGS. 1 and 2 are arranged such that the strands 32 are substantiallyparallel to one another when strands 32 are pulled taut (i.e., when weldstrips 31 are drawn away from one another). In addition, adjacent pairsof strands 32 may have even intervals therebetween, such that asubstantially constant tensile strength of tensioning structure 3 ismaintained across the longitudinal extent of weld strips 31. In anexemplary embodiment, strands 32 may extend along the entire width ofweld strips 31, as illustrated in FIGS. 1 and 2 , such that a large areaof contact between strands 32 and weld strips 31 is achieved. Forclarity, FIGS. 1 and 2 illustrate only a limited number of strands 32affixed to strips 31 in this way, it being appreciated that all strands32 in a tensioning structure 3 may be so affixed.

Strands 32 include first and second terminal ends 34 positioned alongfirst longitudinal edges 36, 38 of strips 31. Strands 32 extends throughsecond longitudinal edges 40, 42 of strips 31 that are parallel andspaced apart from first longitudinal edges 36, 38. Strips 32 have alength 44 extending along longitudinal edges 36, 38, 40, 42 and a width46 defined between respective first longitudinal edges 36, 38 and secondlongitudinal edges 40, 42. Strips have upper surfaces 48, 50 and lowersurfaces 52, 54. When attached to upper and lower sheets 1, 2, strands32 are bent to form a first leg 56, relative to the bend, that extendsalong gap portion 33 and a pair of second legs 58 having a lengthsubstantially equal to width 46 of strips 32.

Together strands 32, with or without reinforcing strands 5, cooperate todefine a tensile sheet/tensile sheet material that has a first side anda second side. When provided with reinforcing strands 5, strands 32 andreinforcing strands 5 cooperate to define holes 34 that extend from thefirst side of the tensile sheet to the second side of the tensile sheet.Each hole 34 is defined by a pair of adjacent strands 32 and the tworeinforcing strands 5 positioned near the respective ends of strands 32.As such, each hole 34 extends from one pair of weld strips 31 to theother pair of weld strips 31 with portions of the holes 34 covered byrespective pairs of weld strips 31. For each respective pair of weldstrips 31, one weld strip 31 is positioned on the first side of thetensile sheet defined by strands 32 and the other weld strip 31 ispositioned on the second side of the tensile sheet. During welding ofweld strips 31, the tensile sheet defined by strands 32 is positionedbetween welds strips 31 of the respective pairs of weld strips 31.Strands 32 of the tensile sheet provide portions of the tensile sheetthat extend perpendicular to longitudinal edges of weld strips 31. Thetensile sheet has four sides. Two sides extend along the terminal endsof strands 32. The other two sides extend along the outermost strands 32adjacent terminal ends of weld strips 31. Reinforcing strands 5 of thetensile sheet 5, when provided, provide portions of the tensile sheetthat extend from one side of these sides to the opposite side of thefour-sided sheet.

When tensioning structures 3 are affixed to upper and lower sheets 1, 2,air mattress 10 has different ply counts at different locations. Forexample, air mattress 10 has a single ply count at portions of upper andlower sheets 1, 2 that are spaced apart from tensioning structures 3 andhas a triple ply count at portions of upper and lower sheets 1, 2 thatare adjacent to the tensioning structure. For example, upper sheet 1defines a single ply count away from tensioning structure 3 andcooperates with the pair of weld strips 31 of an adjacent tensioningstructure 3 to define a triple ply count. In embodiments using a singleweld strip 31, the ply count is only two where upper sheet 1 is adjacentto such a tensioning structure 3.

In one exemplary application shown in FIGS. 3 and 4 , a number oftensioning structures 3 are used in an inflatable structure such as airmattress 10, which includes a sleeping surface at upper material 1 and aground-contacting surface at lower material 2. Annular side band 4 isfixedly connected or welded to the peripheries of the upper material 1and the lower material 2 to form an inflatable chamber. A valve 6 may beprovided to facilitate inflation and deflation of the mattress 10.

Although mattress 10 is shown as a single layer, double layers may alsobe provided. Additional mattress features may also be provided such asthose shown in U.S. Pat. No. 7,591,036 titled Air-Inflated Mattress, theentire disclosure of which is expressly incorporated by referenceherein. In addition to mattresses, tensioning structure may be used inother inflatable products such as inflatable boats, inflatable islands,floatation devices, swimming pools, inflatable slides, and any otherinflatable devices.

Each of the plurality of tensioning structures 3 is welded torespectively opposed portions of the inner surfaces of upper and lowermaterials 1, 2, as described in detail above. As shown in FIGS. 3 and 4, the tensioning structure 3 of the illustrated embodiment defines anoverall longitudinal extent (that is, along the longitudinal directionof weld strips 31) corresponding to the width or length of the sleepingand ground-contacting materials 1, 2 of mattress 10.

As noted above, tensioning structures 3 are connected to upper and lowermaterial 1, 2 by weld strips 31. Such welding is accomplished byabutting one of weld strips 31 to one of upper and lower materials 1, 2and then applying heat to melt and fuse the material of weld strips 31to the abutting material. In an exemplary embodiment, weld strips 31 andupper and lower material 1, 2 are both made of PVC, and the weldingprocess is accomplished by applying 105 degree Celsius heat forapproximately 0.5 seconds. Upper and lower sheets 1, 2 and weld strips31 have thicknesses ranging from 0.15 to 1.0 millimeters with 0.34millimeters being preferred for upper and lower sheets 1, 2 and 0.18millimeters being preferred for weld strips 31. Weld strips 31 arepreferably 12.7 millimeters wide and may range from 1 to 100 millimeterswide. The PVC used preferably has a tensile strength ranging from atleast 7 kgf/cm to 73 kgf/cm and a density ranging from 0.8-2.5 grams percentimeter cubed with a preferred density of 1.5 grams per centimetercubed. Being made of PVC, weld strips 31 and upper and lower sheets 1, 2are plastic sheets that are a integral, homogenous, non-fibrous,non-fabric material. During assembly of tensioning structures 3, strands32 do not pierce weld strips 31, but are sandwiched between therespective pairs of weld strips 31.

In FIGS. 3 and 4 , tensioning structures 3 are welded to upper and lowermaterial 1, 2 along a substantially linear path, with the plurality ofstructures 3 substantially parallel to one another and equally spacedacross materials 1, 2. However, it is contemplated that the weldinggeometry may take any other suitable geometry, such as a wave-like path,I-shaped path, Z-shaped path or V-shaped path. One exemplary alternativegeometry is a cylindrical or columnar arrangement, as illustrated inFIGS. 5 and 6 . In this arrangement, upper and lower weld strips 31 areeach connected at their ends in an end-to-end manner to form an arcuatering, such as a circular ring as illustrated. The plurality of strands32 between the upper and lower weld strips 31 thus form a closedcolumnar periphery, thereby forming the body of a column. Upon assemblyof inflatable bed 10, this column is welded to upper and lower materials1, 2 in a similar fashion as described herein with respect to linearlyarranged tensioning structure 3.

When mattress 10 is inflated, the introduction of pressurized air intothe cavity of mattress urges upper and lower materials 1, 2 apart fromone another. When sufficiently pressurized, strands 32 become taut andtensioning structures 3 prevent any further spreading apart of upper andlower materials 1, 2 in the vicinity of each tensioning structure 3.Further pressurization causes further tensile stress within tensioningstructures 3, and additional forces on the weld between tensioningstructures 3 and the adjacent material.

In an exemplary embodiment of mattress 10, tensioning structure 3includes as few as one strand every two centimeters, 1, 2, 3, 4, strandsper centimeter of longitudinal extent of weld strips 31, or as much as5, 10, 15, 20, 30, 40, 50, or more strands per centimeter, or may haveany number of strands per centimeter within any range defined by any ofthe foregoing values. According to the preferred embodiment, there isabout 2.8 millimeters between strands (i.e., 3.6 strands percentimeter). Strands 32 may be made of regular cotton, polyester, nylonthread made of multiple filaments twisted together, of the typetypically used in clothing seams, or any other strand types. Theseregular threads provide substantial tensile strength at a very low cost.According to alternative embodiments, strands 32 may be woven togetherto form a fabric. According to another embodiment, non-woven fabric maybe used to form the portion of tensioning structure 3 extending throughthe gap between sheets 1, 2.

As shown in FIG. 3 , the distance between adjacent tensioning structures3 is much greater than the distance between adjacent strands of eachtensioning structure 3. The distance between adjacent tensioningstructures 3 is also greater than the gap between upper and lower sheets1, 2. Similarly, the distance between adjacent tensioning structures 3is greater than width 46 of strips 31 so that strips 31 of adjacenttensioning structures 3 are spaced apart.

According to the present disclosure, the threads may range fromdiameters of 0.1 to 1.0 millimeters. According to the preferredembodiment, the thread has a diameter of 0.2 millimeters. According tothe present disclosure, the tensile strength of the threads may rangefrom 0.2 kgf to 10 kgf per thread. According to the preferredembodiment, the tensile strength of the thread is 3 kgf per thread.According to the preferred embodiment, the threads have a density rangefrom 0.01 to 0.3 grams per meter. According the preferred embodiment,the threads are 0.085 grams per meter. Of course, it is appreciated thatother materials could be used, such as monofilament lines, metal wiresor cables, plastic and the like.

The above-described exemplary arrangement of tensioning structure 3yields a strong finished product suitable for use in a wide variety ofinflatable products. In exemplary embodiments, tensioning structure 3has strands 32 with an overall axial span between 5 centimeters and 65centimeters, rendering strands 32 suitable to span a correspondinglysized gap formed between the spaced-apart weld strips 31. Therefore,this exemplary embodiment is suitable for use in mattress 10 having aninflated thickness approximately equal to the axial span of strands 32.This exemplary embodiment further uses the regular thread material notedabove with a strand density in the ranges given above. The resultingexemplary tensioning structure 3 has an overall tensile strength between5.9 and 23.3 kgf per linear centimeter (where linear centimeters aremeasured along the longitudinal extent of weld strips 31).

When mattress 10 is inflated, tensioning structure defines an operablearea along its longitudinal extent and across the gap between upper andlower materials 1, 2. More particularly, the area occupied by tensioningstructure 3 is defined as the total area of the gap between the materialsheets joined by tensioning structure 3, with such gap measured alongthe longitudinal extent of the tensioning structure such that themeasured area is inclusive of each of the plurality of strands 32. Wheretensioning structure 3 is linearly arranged and upper and lowermaterials 1, 2 are parallel to one another (as shown, for example, inFIGS. 3 and 4 ), this area is simply the longitudinal extent oftensioning structure 3 multiplied by the space between upper and lowermaterials 1 and 2. Where tensioning structure 3 takes a non-linear path(such as the columnar, arcuate path shown in FIGS. 5 and 6 , forexample), or upper and lower materials 1 and 2 are non-parallel, theabove-described method for measuring area still results in an accurateoperable area.

The above-described exemplary arrangement of tensioning structure 3achieves high tensile strength while promoting light weight and lowpacked volume of the finished inflatable product. According to thepresent disclosure, strands 32 and the area between strands 32 define agap portion 33 (see FIG. 1 ) of tensioning structure 3 spanning the gapbetween upper and lower materials/sheets 1, 2 that maintains a spatialrelationship between the first and second sheets when mattress 10 isinflated. As shown in FIG. 1 , the collection of strands 32 that definethis gap portion 33 having an extent 35 measured along the surface of atleast one of first sheet 1 and second sheet 2. Strands 32 of this gapportion 33 of tension structure 3 collectively occupy a volume. Gapportion 33 has an operable area defined by extent 35 of gap portion 33(also closely approximate to a length of weld strips 31) and length 37of strands 32. The operable area is occupied by strands 32 of tensioningstructure 3 and defines a total area of the gap between first sheet 1and second sheet 2, as measured along extent 35 of gap portion 33 oftensioning structure 3. For example, if strands 32 of an example tensionstructure have a length 37 of 100 millimeters between first and secondsheets 1, 2 and extent 35 of gap portion 33 is 100 millimeters, theoperable area of gap portion 33 defined by strands 32 is 10,000 squaremillimeters. Assuming that there are 3.6 strands per centimeter, therewill be 3,571 millimeters of strands 32 within the 10,000 squaremillimeter operable area. If strands 32 have a diameter of 0.2millimeters, the total volume occupied by strands 32 will be 112.2millimeters cubed. In this example, gap portion 33 of tensioningstructure 3 defines an operable area-to-volume ratio of 89.13millimeters squared per millimeters cubed (ex. 10,000 millimetersquared/112.2 millimeters cubed). According to the present disclosure,the operable area-to-volume ratio may range from 10 to 3,000 millimeterssquared per millimeter cubed.

Because of use of strands 32 rather than PVC sheets, the overall weightof mattress 10 can also be reduced. Gap portion 33 of tensioningstructure 3 defined by strands 32 has a total weight and operable area,as discussed above. In the above example, the operable area was 10,000square millimeters (100 millimeters by 100 millimeters) and there were3.6 strands per centimeter. This results in 3,571 millimeters of thread.At a density of 0.085 grams per meter of thread, the total thread willweigh 0.304 grams. As a result, an operable area-to-weight ratio will beabout 32,941 square millimeters per gram (or 329,412 square centimetersper kilogram) in the preferred embodiment (ex. 10,000 squaremillimeters/0.304 grams). According to some embodiments of the presentdisclosure, the operable area-to-weight ratio is between 8,000 and5,000,000 square centimeters per kilogram. According to otherembodiments, the operable area-to-weight ratio is between 12,500 and2,500,000 square centimeters per kilogram. According to otherembodiments, the operable area-to-weight ratio is between 20,000 and1,000,000 square centimeters per kilogram.

Because of use of strands 32 rather than PVC sheets, the averagethickness of gap portion 33 of tensioning structure 3 extending betweenfirst and second sheets 1, 2 can also be reduced. Gap portion 33 oftensioning structure 3 defined by strands 32 has an average thicknessand operable area, as discussed above. The average thickness is reducedby the nominally circular cross section of strands 32 and the gapsbetween each strand 32.

For example, the maximum thickness of gap portion 33 is the diameter ofstrands 32 (0.2 millimeters in the above example). The minimum thicknessof gap portion 33 is zero in unoccupied areas between strands 32. Whenaveraged over the total area of gap portion 33 occupied by strands 32and the total area of gap portion 33 without strands 33, the averagethickness is less than the diameter of strands 32. Furthermore, if thedistance between strands 32 is increased, the average thicknessdecreases because more of gap portion 33 is unoccupied by strands (i.e.,the amount of gap portion 33 with zero thickness increases, whichdecreases the average thickness of gap portion 33).

In the above example, the operable area was 10,000 square millimeters(100 millimeters by 100 millimeters) and there were 3.6 strands percentimeter (or 2.8 millimeter from strand 32 to strand 32). In contrastto the maximum thickness of a circular thread, which is the diameter,the average thickness of a circular thread is pi*diameter/4. Usingstrands 32 with a diameter of 0.2 millimeters, results in averagethickness of 0.157 millimeters for each strand 32. Because of the gapsbetween strands 32, the average thickness of gap portion 33 defined bystrands 32 and the gaps therebetween is 0.0112 millimeters (i.e. 2.8millimeters between strands 32 has a thickness of zero, which reducesthe average thickness of gap portion 33 to much less than the averagethickness of strands 32). According to some embodiments of the presentdisclosure, the average thickness of the gap portion of tensioningstructure 3 is between 0.0003 to 0.1 millimeters. According to otherembodiments, the average thickness is between 0.001 and 0.05millimeters. According to other embodiments, the average thickness isbetween 0.005 and 0.02 millimeters.

Turning now to FIG. 7 , an apparatus 20 suitable for manufacturingtensioning structure 3 is shown. To operate apparatus 20 to this end, aplurality of strands 32 are provided from a bulk thread supply 11, whichmay be a yarn stand containing several spools of yarn for example.Thread supply 11 continuously delivers the plurality of strands 32 viastrand guide A, which includes a plurality of apertures through whichindividual strands 32 pass after delivery from thread supply 11 andbefore incorporation into bulk tensioning structure material 30 (shownin FIG. 9 and described below). Strand guide A maintains uniform spacingof strands 32 from one another, and arranges strands 32 parallel to oneanother such that the plurality of strands 32 are substantially planar.The width of weld strips 31, the distance between neighboring pairs ofweld strips 31, and the spacing between neighboring pairs of strands 32can be set to any values as required or desired by an intended use, suchas in a particular inflatable product.

These planar, parallel and even spaced strands 32 are then passed in towelder 40, as shown in FIG. 7 . Welder 40 may be a thermofusion device,using heat to join two plastic materials together, or may be ahigh-frequency welder, in which electromagnetic waves take advantage ofexcitable chemical dipoles in the plastic material to soften and jointhe materials to one another. Moreover, any suitable welding method maybe employed by welder 40, as required or desired for a particularmaterial and process. Another alternative is to forego a welding processand use adhesive to join strands 32 to weld strips 31. Where adhesiveconnection is utilized, welder 40 may be replaced by a similarlyarranged adhesive device, such as a gluing device. Yet anotheralternative is to utilize a sewing machine to mechanically join weldstrips 31 to strands 32. Moreover, weld strips 31 need not be welded toupper or lower materials 1, 2, and the term “weld strip” as used hereinrefers to any strip of material suitable for affixation to anothermaterial, whether by application of heat, application of adhesive,mechanical joining methods such as sewing and riveting, or any othersuitable method.

Weld strips 31, having a length corresponding to the width of thearranged plurality of strands 32, are positioned on lower dies B1 ofwelder 40. Strands 32 are advanced over weld strips 31 as illustrated,and upper dies B2 are then lowered into contact with weld strips 31.Energy (i.e., heat or electromagnetic waves) is applied to fixedlyconnect the weld strip 31 with each of the plurality of strands 32 suchthat the respective strands 32 are fixed in the spaced apart andparallel configuration dictated by strand guide A. When so fixed, bulkmaterial 30 (FIG. 9 ) is complete and ready for use.

The finished bulk material 30 may then be delivered to a take-up device(not shown), such as a spool or roll. This allows bulk material 30 to becontinuously produced and stored for later use. Bulk material 30 can beconverted into tensioning structure 3 (FIG. 2 ) by cutting down thecenter of weld strip 31. Tensioning structure 3 can then be applied tovarious inflatable products by trimming the length and width thereofaccording to the dimensions of the product.

As noted above, reinforcement strand 5 may be added to tensioningstructure 3 to further improve the strength thereof, including thetensile strength of weld strips 31. To add at least one reinforcementstrand 5 to bulk material 30, reinforcement strands 5 are arrangedperpendicular to the plurality of strands 32, and abutting therespective weld strips 31. Upper die B2 of welder 40 is pressed down tofixedly connect the weld strips 31 to both reinforcement strands 5 andthe plurality of strands 32, as described above. Reinforcement strands 5are illustrated in FIG. 3 but omitted from FIG. 4 for clarity.

As shown in FIG. 4 , tensioning structures 30 are positioned within band4 and welded to upper and lower sheet 1, 2. Although shown asperpendicular to sheets 1, 2 in FIG. 4 , after welding, weld strips 31lay flat on sheets 1, 2 after welding as shown in the lower portion ofFIG. 1 . Similarly, in mattresses 10 of FIGS. 6, 21, 23, and 28 , weldstrips 31 are shown perpendicular to sheets 1, 2, but will lay flat onsheets 1, 2 upon welding as shown in the lower portion of FIG. 1 .

As illustrated in FIGS. 8 and 9 , bulk material 30 (FIG. 9 ) may beformed using a single layer of weld strips 31 connecting to strands 32.In another exemplary embodiment shown in FIGS. 10 and 11 , bulk material30 may be manufactured as a dual layer structure using a pair of weldstrips both above and below strands 32. The use of two mutually opposedweld strips employs a gripping action to “trap” or capture the strands32 therebetween, thereby contributing to a high-strength couplinginterface. When implemented in an inflatable product, the resultingdual-layer tensioning structure 3 has improved strength and can bewelded to upper or lower material 1, 2 (FIGS. 1, 3 and 4 ) on eitherside. As shown in FIGS. 10 and 11 and discussed above, at least onereinforcement strand 5 may also be captured between the weld strips 31.

2. Sheet-Backed Tensioning Structures with Affixed Strands.

An alternatively arranged tensioning structure is shown in FIGS. 12 and13 as tensioning structure 103. Structure 103 is substantially similarto tensioning structure 3 described above, with reference numerals ofstructure 103 analogous to the reference numerals used in structure 3,except with 100 added thereto. Elements of structure 103 correspond tosimilar elements denoted by corresponding reference numerals ofstructure 3, except as otherwise noted.

Tensioning structure 103 includes a plurality of strands 32 which areevenly spaced and arranged substantially parallel to one another, in asimilar fashion to tensioning structure 3 described above. However,tensioning structure 103 includes weld sheet 131 in place of weld strips31 of structure 3. Rather than affixing the ends of strands 32 to weldstrips 31, the entire length of strands 32 are affixed to weld sheet131. Weld sheet 131 serves to provide for proper positioning andprotection of the plurality of strands 32, such as to avoid knotting ordamage of strands 32 during practical use. However, because tensioningstructure 103 includes strands 32 embedded therein, weld sheet 131 doesnot need to bear significant tensile loads and can be kept to a minimalthickness. For example, weld sheet 131 may be 0.10 millimeters inthickness.

In FIGS. 12 and 13 , a single weld sheet 131 is used, though otherarrangements are contemplated. FIG. 14 , for example, illustratestensioning structure 103 (FIG. 13 ) with an extra weld sheet 131 appliedopposite the first weld sheet 131. Similar to the embodiment oftensioning structure 3 using mutually opposed weld strips 31 (FIGS. 10and 11 ), the mutually opposed weld sheets 131 may be used toencapsulate strands 32.

FIGS. 15 and 16 illustrate tensioning structure 203, which issubstantially similar to tensioning structure 3 described above, withreference numerals of structure 203 analogous to the reference numeralsused in structure 3, except with 200 added thereto. Elements ofstructure 203 correspond to similar elements denoted by correspondingreference numerals of structure 3, except as otherwise noted. However,structure 203 represents a hybrid approach combining elements oftensioning structures 3 and 103, in which a plurality of weld strips 31are used to encapsulate a portion of strands 32 between strips 31 andweld sheet 131. The addition of weld strips 31 to the weld sheet 131improves the strength of the weld connection between tensioningstructure 203 and the adjacent product material (e.g., upper and/orlower material 1, 2 of inflatable bed 10 shown in FIGS. 2 and 3 ).

FIG. 17 illustrates tensioning structure 303, which is substantiallysimilar to tensioning structure 3 described above, with referencenumerals of structure 303 analogous to the reference numerals used instructure 3, except with 300 added thereto. Elements of structure 303correspond to similar elements denoted by corresponding referencenumerals of structure 3, except as otherwise noted. Moreover, structure303 incorporates all the elements of tensioning structure 203 but adds asecond, lower layer of weld strips 31 attached to weld sheet 131opposite the first, upper layer of weld strips 31. Thus, there is adual-layer structure of opposing weld strips 31 further augmenting weldsheet 131, rendering tensioning structure 303 very strong and robustboth along the extent of strands 32 and at the weld between strands 32and the adjacent material, e.g., material 1, 2 of inflatable bed 10(FIGS. 3 and 4 ).

Turning to FIGS. 18 and 19 , yet another tensioning structure 403 isillustrated. Tensioning structure 403 is substantially similar totensioning structure 3 described above, with reference numerals ofstructure 403 analogous to the reference numerals used in structure 3,except with 400 added thereto. Elements of structure 403 correspond tosimilar elements denoted by corresponding reference numerals ofstructure 3, except as otherwise noted. However, the plurality ofstrands 32 used in structure 403 are discontinuous. As shown in FIGS. 13and 14 , the plurality of strands 32 may be trimmed to any desiredlength, and then affixed to weld sheet 131 by hot pressing. Uponinstallation into an inflatable product use, the affixed strands 32 maybe cut to length, and welded into place as described above. Thus, usingtensioning structures 403 has the potential to reduce consumption of thematerial used for strands 32 and avoid unnecessary waste thereo, therebylower material cost.

Optionally, as shown in FIG. 20 , each end of the weld sheet 131 (i.e.,at the ends of strands 32) may include a reinforcing strand 5 arrangedsimilarly to tensioning structure 3 discussed above. Reinforcing strands5 are omitted from FIG. 21 for clarity.

The sheet-backed embodiments illustrated as tensioning structures 103,203, 303 and 403 in FIGS. 12-19 may be integrated into an inflatabledevice in a similar fashion as tensioning structures 3 described above.For example, FIGS. 20 and 21 illustrate integration of tensioningstructures 103 into inflatable bed 10, which is accomplished by the samemethod as described above.

Tensioning structures 103, 203, 303 and 403 may also be formed into avariety of geometric configurations, as discussed above with respect totensioning structure 3. These configurations include a wave-like path,I-shaped path, Z-shaped path or V-shaped path. As illustrated in FIGS.22 and 23 , is a cylindrical or columnar arrangement may also beutilized. In this arrangement, weld sheet 131 (and upper and lower weldstrips 31, if present) is connected at its ends in an end-to-end mannerto form an arcuate ring, such as a circular ring as illustrated. Theplurality of strands 32 between thus cooperate with the material of weldsheet 131 to form a closed columnar periphery, thereby forming the bodyof a column. The axial ends of this columnar structure can then bewelded to upper material 1 and lower material 2, respectively, ofinflatable bed 10.

Turning now to FIG. 24 , an apparatus 120 suitable for manufacturingtensioning structures 103, 203, 303 or 403 is shown. Operation ofapparatus 120 is accomplished by first supplying a plurality of strands32 from a yarn stand or other stock of yard, as described above withrespect to apparatus 20. Strands 32 are continuously delivered viastrand guide A, described above, which provides uniformly spaced apartand parallel strands 32 to the downstream welder 140.

Welder 140 includes a conveying roller C downstream of strand guide A,which continuously delivers a weld sheet 131 of width sufficient tocorrespond to the width of the plurality of strands 32. Downstream ofroller C, the plurality of strands 32 are near to or abutting weld sheet131.

The plurality of strands 32 and weld sheet 131 then advance togetherthrough hot roller D, which heats and compresses the material such thatstrands 32 become fixed to the softened material of weld sheet 131.After passage through roller D, tensioning structure 103 as shown inFIG. 13 is complete. The bulk material for tensioning structure 103 maybe wound onto a take-up spool for later cutting into a tensioningstructure 103 of appropriate size for a particular application.

When the thus tensioning structure 103 is applied to an inflatableproduct such as inflatable bed 10 (FIGS. 21 and 22 ), the weld sheet 131may have a relatively small thickness given the level of internalpressure (and, therefore, tension) expected to be encountered bystructure 103 during inflation and use of the product. For example, thethickness may be reduced by 20%-40% with respect known internaltensioning structures lacking strands 32. Because strands 32 arepositioned and configured to bear the tensile loads applied totensioning structure 103, weld sheet 131 need only provide for properpositioning and protection of the plurality of strands 32, such as toavoid knotting or damage of strands 32 during practical use. In oneexemplary embodiment, the thickness of weld sheet 131 may be as small as0.10 millimeters.

Where a second weld sheet 131 is added to tensioning structure 103, asshown in FIG. 14 and described above, a second roller C (not shown) maybe provided opposite the illustrated roller C of FIG. 24 , such thatrollers C are disposed on either side of strands 32. Both sheets 131 arethen passed through the hot pressing roller D, capturing strands 32between the two layers of plastic sheets.

Where a plurality of weld strips 31 are added to create tensioningstructure 203, as shown in FIGS. 15 and 16 and described above, afinished tensioning structure 103 made using apparatus 120 may befurther processed using apparatus 20 as shown in FIG. 7 and describedabove. After the intermediate sheeted product equivalent to tensioningstructure 103 exiting from hot rollers D, weld strips 31 may be added toone or both sides of the intermediate sheeted product. At least onereinforcement strand 5 may be added as required or desired, such thatreinforcement strands 5 are perpendicular to the plurality of strands32, as described in detail above.

Where weld strips 31 are added to both sides of a sheeted intermediateproduct to create tensioning structure 303, a process similar to theabove may be employed in which an intermediate sheeted product exitsrollers D and receives additional weld strips 31. However, weld strips31 are added to both sides instead of to a single side, in accordancewith the method of manufacturing a dual-layer version of bulk material30 using welder 40 as described above. Of course, at least onereinforcement strand 5 may be added in a similar fashion as previouslydescribed.

3. Weld Strips Joined By V-Shaped Strands.

An alternatively arranged tensioning structure is shown in FIGS. 25 and26 as tensioning structure 503. Structure 503 is substantially similarto tensioning structure 3 described above, with reference numerals ofstructure 503 analogous to the reference numerals used in structure 3,except with 500 added thereto. Elements of structure 503 correspond tosimilar elements denoted by corresponding reference numerals ofstructure 3, except as otherwise noted.

However, strand 532 in tensioning structure 503 have a staggered,V-shaped arrangement, and may be formed from a single strand wound backand forth rather than a plurality of separate and discrete strands asused in tensioning structure 3 for example. As described below in thecontext of the method of manufacture of tensioning structure 503, strand532 may be a single, continuous strand woven between weld strips 31,31′, with the point of each “V” affixed to at least one of the weldstrips 31, 31′.

Turning now to FIG. 29 , an apparatus 220 suitable for manufacturingtensioning structure 503 is shown. Operation of apparatus 220 isaccomplished by disposing a lower pair of weld strips 31 such that thelower pair are substantially parallel and spaced apart upon joiningdevice 540. In the illustrated embodiment, weld strips 31 are unspooledfrom rolls of weld strip material contained within a pair of unreelingdevices 550.

Next, continuous strand 532 is wrapped successively around a set ofadjacent hook-shaped members 541 disposed at either side of joiningdevice 540, with the plurality of hook-shaped members 541 arranged intwo respective rows corresponding to the location of thepreviously-placed lower pair of weld strips 31. In an exemplaryembodiment, hook-shaped members 541 are uniformly spaced from oneanother and arranged at the outer sides of lower pair of weld strips 31,with each row of hook-shaped members 541 offset with respect to theother row. With this arrangement, the continuous strand 532 forms aplurality of end-to-end “V” shaped strands when wrapped aroundsuccessive hook-shaped members 541 in alternating rows thereof, asshown. That is to say, the corner of each “V” is formed at a respectivehook-shaped members 541, and successive corners traced along continuousstrand 532 will alternate between rows of hook-shaped members 541.

Next, a second pair of weld strips 31′ are positioned over the firstpair of weld strips 31, respectively, and are clamped thereto such thateach “V” shaped corner formed by strand 532 is disposed between one ofthe first pair of weld strips 31 and the abutting one of the second pairof weld strips 31′. The second pair of weld strips 31′ may also beunspooled from unreeling devices 550.

Finally, the abutting pairs of weld strips 31, 31′ are joined to oneanother and to strand 532, such as by welding or by one of the otherattachment methods discussed above. For example, weld strips 31, 31′,may be joined by a high frequency welder or another thermofusion device.It is also contemplated that strand 532 can be fixed to weld strips 31,31′, and weld strips 31 can be fixed to weld strips 31′, by adhesive orby sewing.

As with other tensioning structures discussed above, tensioningstructure 503 may be produced and stored in bulk and later applied tovarious inflatable products. The length and width of tensioningstructure 503 may be trimmed to accommodate the internal length or widthof the inflatable product.

In one alternative embodiment, it may be not necessary to provide thesecond layer of weld strips 31′, and instead to fix only the first layerof weld strips 31 to the strand 532. Fixing strand 532 to the singlelayer of weld strips 31 may be accomplished in a similar fashion to thesingle-layer weld strip and weld sheet embodiments described above.

Turning to FIGS. 30-32 tensioning structure 503 may also be providedwith at least one reinforcement strand 5 extending along thelongitudinal extent of at least one of weld strips 31, 31′. Similar tothe uses of reinforcement strands 5 in the embodiments described above,reinforcement strands 5 may be arranged on one of the lower pair of weldstrips 31 and/or between the lower and upper pairs of weld strips 31,31′.

A tensioning structure in accordance with the present disclosure,including tensioning structures 3, 103, 203, 303, 403 and 503 discussedabove, has a high tensile strength along the axial extent of the strands32, 532 extending between respective weld strips and/or along weldsheets. This high tensile strength is complemented with a full-strengthweld between the adjacent material of an inflatable product, which isfacilitated by the full surface-area contact provided by the weld stripand/or weld sheet interface between strands 32, 532 and such adjacentmaterial. In this way, the tensioning structure performs well aninternal structure of the inflatable product, while facilitating anoverall reduction in weight and deflated/folded volume of the inflatableproduct. For example, a loose arrangement of strands 32 is significantlylighter than a one-piece sheet of comparable size and tensile strength.

Where weld sheets 131 are employed, such sheets act to ensure aconsistent position and arrangement of the plurality of strands 32 (or532), thereby prevent such strands from becoming wound or otherwiseentangled with one another. Meanwhile, weld strips 31 can be utilized toprovide a robust structure for welding the tensioning structure into theinflatable product, thereby ensuring that the high tensile strengthoffered by the strands of the tensioning structure is fully realized. Inaddition, the use of weld sheet 131 can significantly reduce the weightof the entire inflatable product with respect to a traditional,relatively thicker one-piece sheet which is also responsible forhandling tensile loading. In other words, weld sheet 131 reduces by20%-40% in thickness with respect to an existing tensioning structureshaving comparable thicknesses of 0.36 mm to 0.8 mm as noted above.

As illustrated in FIG. 33 , tensioning structures 3 have a distance 39between adjacent tensioning structures 3. As discussed above, strands 32have a length 37 that approximates a height 37 of tensioning structures3 when mattress 10 is inflated. During construction of typicalmattresses using PVC tensioning structures (not shown), the height ofPVC tensioning structures is practically limited by the distance betweenadjacent PVC tensioning structures. This limitation is the result of thetypical manufacturing process wherein the PVC tensioning structures areall aligned on a lower sheet 2 and simultaneously welded to lower sheet2. If the PVC tensioning structures are too tall, they will overlapadjacent PVC tensioning structures causing adjacent PVC tensioningstructures to be welded together and resulting in dysfunctional PVCtensioning structures. To increase the height of PVC tensioningstructures, the PVC tensioning structures may be folded in half alongtheir length while one edge is being welded. By folding the PVCtensioning structure, the maximum height may be increased to slightlyless than twice the distance between adjacent PVC tensioning structures(ex. 15 millimeters less than twice the height of the PVC tensioningstructure). Providing more than one fold is impracticable.

Because gap portions 33 of tensioning structures 3 are made of strands32 rather than typical PVC sheets discussed above, they are much moreflexible than typical PVC tensioning structures. As a result of thisflexibility, mattresses 10 can be readily manufactured having heights 37greater than twice distance 39 between adjacent tensioning structures 3.

During manufacture, weld strips 31 of each of the plurality oftensioning structures 3 are aligned in their respective position forwelding to lower sheet 1. The other weld strip 31 of these tensioningstructures 3 are moved adjacent to the weld strip 31 to be welded asshown in FIG. 33. Because of their flexibility, strands 32 bunch on topof themselves or on top of nearby strands 32 allowing multiple layers ofstrands 32 to readily lie on top of one another. By allowing multiplelayers of strands 32 to lie on top of each other, height 37 oftensioning structures 3 can be greater than twice distance 39 betweentensioning structures 3. According to embodiments, length 37 of strands32 may be 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6 or more times longer thandistance 39 between tensioning structures 3.

As shown in FIG. 33 , loops 41 form in strands 32 during bunching andportions of strands 32 may be positioned under weld strip 31 that iscurrently not being welded. Although each strand 32 shown in FIG. 33only has one loop 41 and is only overlapping one other strand 32, eachstrand 32 may have multiple loops 41 and may overlap multiple otherstrands 32, particularly when the distance between stands 32 along weldstrips 31 is shorter than that illustrated in FIG. 33 .

In addition to the bunching arrangement shown in FIG. 33 to facilitatewelding of weld strips 31 to lower sheet 2, other orientations of longstrands 32 can be used to prevent a portion of one tensioning structure3 from overlapping an adjacent tensioning structure 3 during welding.For example, as shown in FIG. 35 , strands may be collected in piles 43to account for moving welds strips 31 of each tensioning structure 3adjacent each other. The turns of piles 43 account for the decreaseddistance between weld strips 31 when weld strips 31 are moved together.According to another example, weld strips 31 of each tensioningstructure 3 are shifted along the extent or length of tensioningstructures 3 as shown in FIG. 36 . The shifting results in strands 32forming acute angles with weld strips 31 and accounts for the decreaseddistance between weld strips 31. By accommodating strands 32 that arelonger than the distance between adjacent tensioning structures 3,tensioning structures 3 may be made taller without interfering with theprocess of welding tensioning structures 3 to upper and lower sheets 1,2. As mentioned above, strands 32 may be longer than shown in FIGS.33-36 . With such longer strands 32, more or larger loops 41(FIG. 33 ),larger and/or taller piles 43 (FIG. 35 ), or greater shifting (FIG. 36 )may be used to accommodate the longer strands 32 to avoid tensioningstructures 3 overlapping during welding.

When prepared for shipping or storage, mattresses 10 are deflated.During deflation, strands 32 may bunch as shown in FIG. 33 . Further,strands 32 from adjacent tensioning structures 3 will contact each otherand may become interleaved with strands 32 from one tensioning structure3 positioned between strands 32 of another tensioning structure.Further, because strands 32 are very flexible, they collapse readilywhen contacted by other structures when mattress 10 is deflated forshipping or storage. For example, when strands 32 contact upper or lowersheets 1, 2 when deflated, they comply to upper and lower sheets 1, 2 toallow upper and lower sheets 1, 2 to compact more closely. At leastpartially because of this compaction, the overall deflated volume ofmattress 10 is reduced when compared to mattresses using PVC sheettensioning structures. When collapsed, strands 32 from a tensioningstructure 3 may become interleaved with strands 32 from the sametensioning structure 32, loops 41 may form, piles 43 may form, and/orstrands 32 may become angled to weld strips 31 in a manner similar tothat shown in FIG. 36 .

As shown in FIG. 34 , when collapsed, strands 32 may be oriented indifferent directions with some overlapping as shown in the bottom twostrands 32 and other following substantially the same direction as shownin the top three strands 32. Some strands 32 collapse in directions thatare not perpendicular to the extent of weld strips 31. For example, thelowest-most strand 32 in FIG. 34 leaves left-most weld strip 31 is aperpendicular direction to this weld strip 31, turns up to be parallelto this weld strip 31, returns to perpendicular to this weld strip 31,turns down to be parallel to this weld strip 31, and then loops underthis weld strip 31 to attached to the other weld strip 31 in aperpendicular direction to the other weld strip 31. According to someembodiments, the overall folded or deflated volume of mattress 10 may be8-25% less than comparable mattresses with PVC sheet tensioningstructures. According to the preferred embodiment, the volume is about16% less.

A tensioning structure in accordance with the present disclosure is alsoa low-cost option for imparting a desired structure and shape to aninflatable device. For example, a large reduction in PVC material may beachieved by use of the present tensioning structure, as compared to aone-piece sheet of comparable size and tensile strength.

While the disclosure has been described as having exemplary designs, thepresent disclosure can be further modified within the spirit and scopeof this invention. This application is therefore intended to cover anyvariations, uses or adaptations of the disclosure using its generalprinciples. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this disclosure pertains.

What is claimed is:
 1. An inflatable product having a pressurizableinflatable chamber; the product comprising: a first sheet; a secondsheet, the first and second sheets configured to become spaced apart todefine a gap when the inflatable chamber is pressurized; a valve incommunication with the inflatable chamber to facilitate inflation anddeflation of the inflatable chamber; a plurality of first weld stripswelded to the first sheet; a plurality of second weld strips welded tothe second sheet; and a plurality of strands, each strand defining atleast one V-shape having: a first end affixed to the first sheet,wherein the first end is captured between the first sheet positioned onone side of the first end and one of the first weld strips positioned onan opposing side of the first end; a second end affixed to the firstsheet; and an intermediate corner positioned between the first andsecond ends and affixed to the second sheet, wherein the intermediatecorner is captured between the second sheet positioned on one side ofthe intermediate corner and one of the second weld strips positioned onan opposing side of the intermediate corner.
 2. The inflatable productof claim 1, wherein each strand is contained within a single plane. 3.The inflatable product of claim 2, wherein the single plane isperpendicular to the first and second sheets.
 4. The inflatable productof claim 1, wherein each strand is contained within a plane, and therespective planes of the plurality of strands are parallel to oneanother.
 5. The inflatable product of claim 1, wherein both the firstand second ends are captured between the first sheet positioned on oneside of the first and second ends and one of the first weld stripspositioned on an opposing side of the first and second ends.
 6. Theinflatable product of claim 1, wherein the first weld strips arevertically aligned with the second weld strips.
 7. The inflatableproduct of claim 1, further comprising: a plurality of third weld stripspositioned between the first sheet and the first weld strips; and aplurality of fourth weld strips positioned between the second sheet andthe second weld strips.
 8. The inflatable product of claim 1, whereineach strand defines a plurality of interconnected V-shapes, such thatthe second end of one V-shape corresponds to the first end of animmediately adjacent V-shape to form a corner.
 9. The inflatable productof claim 1, wherein the entire axial extent of each of the plurality ofstrands is spaced apart from the entire axial extent of each neighboringstrand, such that the plurality of strands are evenly spaced apart. 10.The inflatable product of claim 1, wherein: the first end interruptsfull surface-area contact between one of the plurality of first weldstrips and the first sheet; and the intermediate corner interrupts fullsurface-area contact between one of the plurality of second weld stripsand the second sheet.
 11. The inflatable product of claim 1, wherein theinflatable product is a rectangular mattress having a first side and asecond side, and wherein each of the plurality of strands extendsbetween the first and second sides of the mattress.
 12. The inflatableproduct of claim 1, wherein the inflatable product is a mattress, thefirst sheet includes a sleeping surface, and the second sheet includes aground-contacting surface.
 13. The inflatable product of claim 1,wherein: the plurality of first weld strips are spaced apart from oneanother across the first sheet; and the plurality of second weld stripsare spaced apart from one another across the second sheet.
 14. Aninflatable product having a pressurizable inflatable chamber, theproduct comprising: a first sheet; a second sheet, the first and secondsheets configured to become spaced apart to define a gap when theinflatable chamber is pressurized; a valve in communication with theinflatable chamber to facilitate inflation and deflation of theinflatable chamber; a plurality of strands, each strand defining aplurality of interconnected V-shapes, and each V-shape having: a firstcorner affixed to the first sheet; a second corner affixed to the firstsheet; and an intermediate corner positioned between the first andsecond corners and affixed to the second sheet; a first weld stripwelded directly to the first sheet with the first corner positionedtherebetween such that the first corner interrupts full surface-areacontact between the first weld strip and the first sheet; and a secondweld strip welded directly to the second sheet with the intermediatecorner positioned therebetween such that the intermediate cornerinterrupts full surface-area contact between the second weld strip andthe second sheet.
 15. The inflatable product of claim 14, furthercomprising at least one reinforcement strand arranged perpendicular tothe plurality of strands.
 16. The inflatable product of claim 14,wherein the first sheet, second sheet, first weld strip, and second weldstrip are all made of polyvinyl chloride (PVC).
 17. The inflatableproduct of claim 14, wherein the first and second weld strips havethicknesses ranging from 0.15 to 1.0 millimeters.
 18. The inflatableproduct of claim 14, wherein the first and second weld strips havewidths ranging from 1 to 100 millimeters.
 19. The inflatable product ofclaim 14, wherein: at least a portion of the first weld strip lays flaton the first sheet; and at least a portion of the second weld strip laysflat on the second sheet.
 20. The inflatable product of claim 14,further comprising: a third weld strip welded directly to the firstsheet; and a fourth weld strip welded directly to the second sheet;wherein a first of the plurality of strands staggers back and forthbetween the first and second weld strips and a second of the pluralityof strands staggers back and forth between the third and fourth weldstrips.